ZyXEL Communications U-336R/RE manual Your modem fails to execute AT commands

Problem

Your modem fails to execute AT commands.

Solutions

1.Make sure the DTR LED is ON. If it is OFF, make sure your communications software is using the same COM port as your modem.

2.You may have omitted the characters AT from the beginning of the command line. These characters must appear at the beginning of each command line.

3.You may have typed the commands when your modem was in data state instead of the command state. To switch from data state to command state, type the escape sequence code +++. To return to the data state, type ATO and press Enter.

Problem

You typed an AT command, but did not receive an OK or 0 result code.

Solutions

1.Your communications software may be using a different COM port than your modem. Be sure both the software and your modem are addressing the same COM port.

2.The E0 and Q1 commands may be in effect, disabling echo and result codes. To verify this in terminal mode, type AT&V0 and press Enter with the modem in command state to view the currently active settings. To enable echo and result codes, type AT E1 Q0 and press Enter.

3.You may have typed the commands when your modem was in the data state instead of the command state. To switch from data state to command state, type the escape sequence code

+++. To return to data state, type ATO and press Enter.

Diagnostics & Troubleshooting 127